Art of sound reproduction



March 29, 1932.-

A. McL. NICOLSON ART OF SOUND REPRODUCTION Filed June 20, 1927 3Sheets-Sheet l INVENTOR ALEXANDER MLEAN NICOLSON March 29, 1932. Mc| c s1,851,208

ART OF SOUND REPRODUCTION.

Filed June 20, 1927 3 Sheets-Sheet 2 INVENTOR ALEXANDER McLEAN NICOLSON5, 7M5,

ATTORN EY March 29, 1932. A. McL. NICOLSON ART OF SOUND REPRODUCTIONFiled June 20, 1927 5 Sheets-$heet AMPLIFIER DETECTOR R.F. AMPLIFIER.

INVENTOR ALEXANDER McLEAN NICOLSON BY 4 2 ATLI'IORNEY Patented Mar. 2 9,1932 & UNITED STATES PATENT OFFICE ALnxAmma ucLnAn NIGOLSON, or NEWiroax, N. Y., ABSIGNOB 'ro COMMUNICATION rArmrrs, me, or NEW YORK, n;1., A conroaArron' or DELAWARE ART 01 SOUND REPRODUCTION Applicationfiled June 20, 1827. Serial No. 199,885.

This invention relates to electrical and acoustic apparatus and moreparticularly to apparatus adapted to reproduce at any desired volumesounds corresponding to eleca trical oscillations, which electricaloscillations may be currents derived from received wireless or radiosignals, speech currents from a tale hone line, audio frequency currentsor radio frequency oscillations modulated at 30 audio frequencies asproduced by electric phonograph apparatus or the like.

One of the difliculties of radio reception 1n the past has been that ofproviding comfortable audition of radio signals for one who desires tohear them without disturbing others in the vicinity who may not wish tolisten: for example, one may desire to listen to incoming radio signalsat a late hour when persons are sleeping in adjoining rooms, or in thecase of sickness where quiet is essential. Under such circumstances inthe past, it has been necessary for the person listening to such-signals to utilize the socalled head telephones if quality ofreproduction was desired. As is well known, head telephones areuncomfortable if worn for any considerable period and it is usually thecase that if one member of a household desires quiet it becomesnecessary to dispense with radio reception during such period. It hasbeen attempted by listeners under such circumstances to obtain loudspeaker reproduction by the use of a volume control to decrease theintensity of sound radiated to such value that it might be comfortablyheard by the listener but without disturbing others. However, as is wellknown, it is not possible under such circumstances to obtainsatisfactory quality of reproduction of speech or music, for the reasonthat when the volume is turned down to such a point that it is inaudibleto those in the vicinity who do not wish to listen, it is usuallyinaudible to the person desiring to listen, or if not inaudible, the lowfrequency response is largely lost and the quality of the sound isdistorted, the reason apparently being that the low frequency soundwaves require a large amplitude of motion of the loud speaker diaphragmin order to be propagated any distance from the loud speaker, and suchamplitudes are not REISSUED obtainable when the volume is decreased to apoint such that the high frequencies are audi le for only a shortdistance. It results, therefore, that in order to hear music or speechof good quality, the listener must place his ear or ears in extremelyclose proximity to the speaker, and this close proxlmity is notobtainable comfortably with the present types of speakers. 1

It is an object of the invention to provide such apparatus which willallow the approach of the ear or ears in intimate and comfortableproximity thereto, and including, if desired, means whereby theoperator'or listener may reduce the volume to a point such that thesounds produced'are clearly and comfortably audible to him with hisear-or ears in proximity to the sound reproducing apparatus, but ofinsuificient intensity to be card at any substantial distance therefrom.

It is still a further object of my invention to provide radio receivingand sound radiating apparatus which may be enclosed within a softresilient comfortable covering having minimum sound absorbingproperties, whereby the apparatus may-be used as a pillow, cushion orthe like, to permit of the comfortable observation by the listener ofthe desired sounds clearly audible to him but inaudible to others inproximity to him, without the necessity of wearing head telephones,which covering may include within itself all apparatus necessary for thereception, selection, amplification, detection and reproduction of radioor like signals at the desired volume, or any desired part of suchapparatus.

It is a further object of this invention to provide apparatus of theclass described and 1 claims. My invention itself, however, both as toits fundamental principles and as to its practical application will bestbe understood by reference to the specification and accompanyingdrawings, in which:

Figures 1, 2 and 3 are diagrammatic views in partial section of variousforms of sound reproducing apparatus enclosed within a soft resilientcovering in accordance with my invention, and including soundreproducing apparatus and means for controlling the volume of soundreproduced, and Figure 1a. is a detail diagrammatic view of a suitable.volume control.

Figure 4 illustrates a slightly different form of supporting frame forthe resilient and yielding envelope.

Figure 5a is a top plan view partly broken away of an arrangement inwhich the framework is dispensed with, and Figure 5b is an elevationview partly in section thereof.

Figure 6 illustrates a similar arrangement but enclosing within thecovering a simple form of radlo receiving and detecting apparatus.

' Figures 7a, 7 b, and 7 c are respectively circuit diagrams of theapparatus shown in Figure 4:, and details of the control mechanism.

Figure 8 is a diagrammatic view of a system in accordance with myinvention in which the sound radiating apparatus is enclosed within thecovering and adapted to receive by inductive or capacitive couplingaudio frequency currents corresponding to received radio signals and thelike.

Figure 9 is a similar view of a slightly modified form of apparatus.

Figure 10 is a diagrammatic view of a still further modified arrangementwhich may be used in accordance with my invention.

In accordance with my invention, I provide sound reproducing andradiating apparatus such as a cone, horn, or sounding board, or aplurality of such devices, adapted to be driven by any suitablemechanism, such for example, as an electro-magnetic or electro staticreceiver or a piezo-electric device such as a crystal of Rochelle salt,and I enclose this sound radiating apparatus within a covering adaptedto support on its outer surface of a layer or resilient and flexiblematerial. The layer of resilient and flexible material is preferablymade up of a substance or substances having minimum acoustic damp-- ingproperties, and supported in a suitable manner by an open grille, meshor similar structure, so as to interfere as little as possible with theradiation of sound, while affording suflicient rigidity to protect theapparatus enclosed within it.

I also provide a volume control which may be in the form of a variableresistance shunted across'the reproducing apparatus whereby the listenermaycontrol the volume of sound reproduced, at will.

In accordance with one aspect ofmy invenattached to the covering. Undercertain con-.

ditions, this pick-up device may be in the form .of a closed or opencircuit adapted to be coupled inductively or capacitively with similarcircuits carrying currents of acoustic frequency, and supplied by theoutput circuit of the radio receiving apparatus, electric phonographapparatus, telephone line or the like.

11 accordance with still another modification of my invention, thepick-up device instead of operating at audio frequency, may operate atradio frequency or carrier frequency, to pick up electrical oscillationsof such frequencies radiated either directly from a transmitter orsecondarily from a receiver adapted to receive such oscillations and toretransmit or reradiate them at the same or difierent frequencies..,

The pick-up device in accordance with the simplest form of my inventionadapted to operate at other than audio frequencies, may comprise asimple tuning system, a crystal or other detector, andsound reproducingapparatus as previously described.

In another form of my invention, such pick-up device may comprise aradio frequency amplifying system, either tuned or untuned, and thedesired detecting and audio frequency amplifying apparatus as well asthe sound radiating apparatus.

Referring now more particularly to Fig. 1,

have shown an arrangement of sound reproducing apparatus in the form ofa pillow: in this ararngement, 1 represents a main frame ring of metal,metal tubing, wood, or the like, having the basic shape of the pillow:if a round pillow is desired, the frame or ring 1 may be circular: if arectangular pillow is desired, the ring l ma be given the appropriateshape. Mounte within this frame or ring 1 isprovided, in this instance,a conical diaphragm 2 of suitable material, such as paper, reinforcedfibre, or the like, secured to the ring 1 at its periphery by means ofan annular hinge 3 of flexible material, such as cloth, paper, leather,or the like. Suitable brackets, braces or cross arms 4, may extendinwardly from the ring 1 to some interior point suchas the center forthe purpose of suporting a suitable driving mechanism 5 for operatingthe diaphragm by means of aconnection 6. The driving mechanism 5 may bean electro-magnet of the usual type, or it may comprise anelectro-static driving mechanism,

- cient strength,

or a piezo-electro crystal device of the types i iii f t tin th or eurpose r0 ec e aphragm and the mechanism conta med withm the pillow, andalso for the pu use of proriding a firm foundation upon w ich may bebuilt a yielding and resilient surface, I provide a pair of covermembers 7 and 8 adapted to be secured in position on opposite sides ofthe r' 1. The cover members 7 and 8 are prefers 1y constructed in amanner to provide the necessary or desired mechanical rigidity while atthe same time interfering as little as ossible with the radiation of thesound from 'aphragm 2. For this urp'ose, these members may be built up0' wire mesh of sumrforated metal plates, wicker work, or the e,aiiording relatively large mechanical strength while at the same timepresenting minimum impedance to the passage of sound waves therethrough.In order to provide for a resilient and yielding sur face, the members'2 and 8 may be, covered with a layer of cloth 10a such as cheese cloth,muslin, or the like, afiording a bed upon which may be built a layer ofresilient and sound conducting material 9.

In order to obtain the best results, the layer of material 9 should besufliciently thick to provide a yielding and resilient surface againstwhich the ears or other members of the body of the listener may bereposed in comfort, while at the same time, this layer of materialshould not introduce any considerable damiping upon the sound waves, atany acoustic equency. Various materials may be used for this purpose,but I have found that the most satisfactory material is ever greenfoliage, such as balsam, hemlock or arbor vitae, pine needles, and thelike. The theoretical explanation of the superior results obtained fromthis material in comparison with other materials, is not entirely clear,but is probably due to the fact that evergreen foliage in quantitybetween spaced surfaces of cloth or similar material, provides arelatively resilient and yielding structure, in which the free spaces ofair are relatively large and in which sound may travel freely, almost asin free air, whereas in the case of materials in which the air spacesare relatively smaller and are more completely filled withmaterial, freemovement of air pressure therethrough is thereby hindered or prevented.At any rate, whatever the theoretical explanation may be, I wish to notethe fact that best results are obtained with the materials specified.

After a layer of the desireddepth of such material has been built up,for example 1" or 2" in thickness, an outer covering 106 may beattached, and finally if desired, an ornamental or decorative cover maybe applied over all, the ornamentation or decoration being chosen tosuit the taste and to harmonize with the setting in which the apparatusis to be used, without interference mth the tree passage of sound.

For the purpose of controlling the operation of the device, leads 11 and12, through which currents of audio irequency are an plied to causeoperation of the device, may provided with a suitable by-pass l3, hereindiagrammatically shown as resistance, but it I will be understood thatan inductance and capacity or any combination of those, may be provided.A suitable control for the by- 13 is extended to the exterior of the iow, for example in the manner shown in igure 1a, wherein there isprovided a resistance suitably mounted in the form of an arc and adaptedto be traversed by a contact a 14 mounted upon a suitable shaft 15, inturn carrying a disc 16, to which cords or chains 17 are attached. Saidcords or chains may pass through suitable o enings in the members 7 and8 and the resi 'ent covering therefor and may terminate in obs, tassels,or the like, such as 18 and 19. In the operation of the device, theloads 11 and 12 are suitably connected to a source of audio freque cycurrentssuch as the output of a radio r eiver a telephone line, anelectric phonograph, or the like, which as will be readily understood,causes vibration of the diaphragm 2, thereb propagating sound wavesthrough the resi ient and yielding cover into the open air. If arelatively large volume of sound is desired, as may be the case whenseveral people wish to listen, impedance of the bypass 13 will be made amaximum by 0 eration of the controls: if, on the other and, one desiresto listen without disturbing others,the impedance of the by-pass may beadjusted to such value that the intensity of the sound is diminished tothe point desired: and it may be decreased to such a point that theoperator may place his ear or cars in intimate and comfortable proximityto the diaphra m. 2 simply by reclining his head against t e pillow inthe ordinary manner, and under such conditions the quality of soundradiated to the ear of the listener will be substantially the same asthat radiated to the ear of the listener in 4 the usual manner. I

Referring now more particularly to Figure 2, I have shown a horn type-ofreproducer 25 in place of the cone 2. By coiling the horn upon itself,it is possible to obtain a horn of relatively great length and widefrequency a response, with consequent improvement in quality, as isknown in the art: in this instance, braces 26 may maintain the horn andoperating mechanism in the desired position. As in the arrangement shownin Figure 1, a pair of supporting members 7 and 8 are provided overwhich is formed a layer of resilient material and the outside coverings,as already described. In addition, a suitable volume control may beprovided having its controls extending outwardly through the outercovering as is also the case for leads 11 and 12.

Referring now more particularly to Figure 3, I have shown a similararrangement except that in this instance the sound radiating element comrises a relatively large plain diaphragm. which may be a true diaphragmoperating as such and constructed of any desired material such as metal,balsa wood, or the like, or may be sufliciently thick and so arranged asto constitute a sounding board.

Referring now. to Figure 4, I have shown an arran ement in which,instead of a framewor of wire mesh, or the like, I have utilized apressed or formed member for example, of fibre, composition or the like,made in sections 7 and 8 as before, but provided in this instance with adepression on one side71 adapted to receive the head of the listener andalso provided with a plurality of perforations 70 to permit freetransmissions of sound waves therethrough.

While I have shown a lar e diaphragm as the sound radiator in this gure,it wlll be understood that other radiators such as those previouslyreferred to may be used in this arrangement if desired.

Under certain conditions, it may be de-v sired to dispense with thesupporting envelope, and such an arrangement is shown in Figures 5a and5b. In this instance, I provide a horn 80, attached to the speaker unit,which horn may be mutilated to provide a dished portion 81 which maybeso constructed as to act as a sounding board, and also as a support forthe flexible envelope. The horn 80 may be provided with a plurality ofholes or openings 82 of any desired shape and disposition for thepurpose of modifying the quality of the sounds reproduced, and ofallowing free distribution thereof to the atmosphere. For the purpose ofpreventing the lling of the envelope from clogging the horn, the hornmay be enclosed in a covering 83 of relatively thin and porous clothsuch as cheese cloth, muslin or the like. A volume control willpreferably be provided as hereinbefore described.

Referring now more particularly to Figure 6, I have shown a modifiedform of apcluded therein are complete in themselves and require noconnection to outside circuits: In this inStance thereImay be providedin addition to the sound reproducing mechanism, a bracket or panel 30supported from ring 1 which maycarry the usual elements of a simpleradio receiving'set, such for example as inductance 31, capacity-32 anda crystal or other detector 33 which may be connected in the circuitshown in Figure 7 a: Antenna and counterpoise or ground conductors maybe attached to the pillow in the form of ribbons, streamers and thelike, or a suitable loop antenna may be formed within the coverin orotherwise attached thereto. In Figures a, 76, and 7c, 35 represents anantenna connected at one end of the coil 31; 37, a counterpoiseconnected at the other end of said coil; 32, a condenser in shunttherewith; 33, a suitable detector such as a crystal; 38, a by-passcondenser, utilized if desired; and 5 and 27 respectively represent thedriving mechanism and sounding board as shown-in Figures 3 and 6. Itwill be understood that the arrangements shown in Figures 1 and 2, 4,7a, and 7b may be utilized, or other suitable sound reproducingmechanism may be substituted for the arrangements shown.

For the purpose of providing for selectivity, coil 31 may be providedwith a plurality of taps 31a, 31b, 31c, and 31d, arranged as desired,and adapted to be connected selectively in circuit by a suitable contact10 secured to disc 41, and operated by means of pull chains 42 and 43.It will be understood that snap switches of any suitable type may besubstituted, if desired, for the arrangement shown, or a continuouslvariable inductance may be provided suc as a variometer. Similarly, thevariation of the capacity may be obtained by providing a pluralit and320?, adapted to be connected in clrcuit by means of a similar contact40, the position of which is controlled b pull chains 42 and 43:similarly, snap switches may be of fixed condensers 32a, 32b, 32c,

substituted for the arrangement shown, or a continuously variablecondenser may be utilized.

The arrangement of Figure6 will provide satisfactory reproduction ofsignals, from nearby broadcasting stations, particularly "when it is notdesired to produce a large ing to a radio frequency amplifier, theoutparatus in which the electrical circuit input of which is supplied toa detector and the detected currents from which are amplified by asuitable audio amplifier: instead of physically connecting the soundreproducing device to the output of the audio frequency amplifier, theoutput currents may be supplied to a suitable open or-closed circuit 47which may be in the form of wires leading to any desired point, and towhich similar wires included within the pillow may be inductively orcapacitively coupled. This permits the movement of the pillow as desiredwithout restriction dueto length of connectleadnond also permits the useof a pluty of speakers operated by the same reiver.

It me be dd to provide one or more stages or audio fre uencyamplification with- Under certain conditions, it me be desired 1 toutilize e. lurelity of such pillows, each receiving on responding to adifferent tronsmitter: in such case, there may he provided rediofrequency amplifying system edeed to receive and radiate signals at recfrequency, either on the same frequencies as r ived, or on difierentfrequencies. For this purpose, there may be provided a redi= stingcircuit d8 ntteched to the output of the emplifier: the amplifier itselfmey1 comprise e. tuned system selectively emp et one frequency or enaperiodic amplifying sys empll g all incoming frequencies: or it may bein the form of e heterodyne which ma increase or decrease the frequencyof a incoming signals by any desired amount, which new frequenciesamplified if desired, may be radiated through the radiating circuit 48.The receiver in such case will preferably comprise a pick-up system withor without radio frequency amlification, a selecting system, a detector,and if desired an audio frequency amplifying apparatus. Such receivermay be utilized also to reproduce si als received from a radiophonograph as s own in Figure 9, WlllCh may conveniently comprise athermionic vacuum tube oscillator 50 having an input circuit comprisincoil 51 and a condenser 52 provided if dzsired, with antenna 53 andcounterpoise 54 of relatively small size. The input circuit may beconnected between the cathode 55 and the control electrode 56, and anout ut circuit is connected between anode 57 and extends through asuitable feed back coil 58 and a microphone or magnetic pick-.

up 59 provided wit a stylus adapted to be driven by a suitable record.The plate oncult is completed through a suitable source of potential forfeeding space current and heatmg the current to t e oscillator 60. Aswill be understood, the microphone or magnetic pick-up 59 serves tomodulate at audio frequencies the radio frequency oscillationgeneratcdby the oscillator 50 which are radiated by the radiating systemcomprisin antenna 53 and counterpoise 54 and the ra iated oscillationsare lcked up by the receiver, detected, ampli ed if desired, andconverted into sound of the desired volume.

Under certain conditions, it may be desired to mount the entireapparatus comprising ravprising a layer 0 am lifier, detector, and audioor within the pillow so shown 1n Fi re 10, in which case a suitable loopmay attached to the fabric, or ilarlysecured to the pillow or on open amtone and counterpoise circuit or ground may be provided in the form ofstreamers, hevin g metallic conductors provided therein attache to thepillow: in any event, the controls for volume and selectivity willpreferably be pro= vided in the form of chains. cords or the like,extending out of the pillow, end eideer sufliciently inconspicuous estobe oticeable, or decoreted in e manner to harmonize with the decorativeefiects thereupon.

While 1 have shown and described the devices herein as e pillow, itshould be understood that my invention is not ited thereto butcontempletes the provision of en upholstered envelope of any sort,whichmey be an article of furniture, such as e chair, end which includesin a recess therein, en ecous= tic radiating system, and also ifdesired, means for controllin the volume within any desired range: and aso any necessary or desired audio frequency amplifying apparatus,detecting device and a radio or carrier fre quency amplifying apparatus,together with the necessary pick-up devices.

While I have shown and described certain preferred embodiments of myinvention, it will be apparent that modifications and changes may bemade therein as will be understood by those skilled in the art, withoutdeparting from the spirit and scope of my invention.

I claim:

1. Acoustic apparatus comprising a loud speaker adapted to convertelectrical oscillations into sound waves corresponding thereto, aprotecting framework surrounding said loud speaker and a yielding andflexible covering having minimum acoustic damping characteristicsmounted upon said framework.

2. Acoustic apparatus comprising an acoustic device adapted to convertelectrical oscillotions into sound waves corresponding thereto, and ayielding dio uen fie ilfhy g1 evergreen foliage mounted upon saidacoustic device.

3. Acoustic apparatus: comprising, in combination, a hollow flexibleenvelope, electrical sound reproducing apparatus positioned within saienvelope, and a layer of soft resilient material extending over thesound radiating portion of said reproducer, said material having amultiplicity of an spaces therein and permitting the passage of soundtherethrough.

4. Acoustic apparatus comprising, in combination, a hollow flexibleenvelope, electrical sound reproducing apparatus positioned within saidenvelope, and a layer of soft, resilient material extending over thesound and flexible covering com radiatin portion of said reproducer,said material ing permeated throughout with air spaces Ipermittmg thepassage 0 sound therethrou 5. coustic apparatus comprising a framework,a hollow yielding and resilient envelope of minimium acoustic dampingcharacteristics, comprising alayer of evergreen foliage mounted uponsaid framework, and sound reproducing apparatus adapted to convertelectrical oscillations into sound waves corresponding thereto, mountedupon said framework within said envelope.

6. Acoustic apparatus comprising an acoustic device adapted to convertelectrical oscillations into sound waves corresponding thereto, ayielding and resilient covering having minimum acoustic dampingcharacteristics mounted upon said acoustic device,saidyielding andresilient covering being arranged to completely cover said acousticdevice to permit the ear of the listener to be placed in intimate andcomfortable proximity thereto without contact with any hard object, andmeans for controlling the intensity of sound produced thereby.

7 Acoustic apparatus comprising a framework, a hollow yieldin andresilient envelope of minimum acoustic ampin characteristics mountedupon said framewor to permit the ear of the listener to be placed inintimate and comfortable roximity to said acoustic device, a loud speaer adapted to convert electrical oscillations into sound wavescorresponding thereto, mounted within said framework and means forcontrolling the intensity of sound produced thereby.

8. Acoustic apparatus comprising an acoustic device adapted toconvertelectrical oscillationsinto sound waves,corresponding thereto, ayielding and resilient covering having minimum acoustic d mpingcharacteristics mounted upon said acoustic device to permit the ear ofthe listener to be placed in intimate and comfortable proximit to saidacoustic device without contact wit any hard object, means forcontrolling theintensity of sound produced thereby, mounted within 'saidcovering, and a flexible operating control for said means extendingthrough said covering.

9. Acoustic apparatus comprising an acoustic device adapted to convertelectrical oscillations into sound waves corresponding thereto, ayielding and flexible covering having minimum acoustic dampingcharacteristics,

enclosing said acoustic device, and means within said covering for suppling electrical oscillations to said acoustic evice without metallicconnection to the source of such oscillations.

10. Acoustic apparatus comprisinga supportin framework an acousticdevice carried trical oscillations into sound waves correspondingthereto, a yielding and flexible covsai framework adapted to convertelec-.

ering having acoustic damping characteristics mounted u on said acousticdevice to permit the ear 0 the listener to be placed in intimate andcomfortable prom'mity thereto and to be supported thereby, and meanswithin said covering for supplying electrical oscillations to saidacoustic device without metallic connection to the source of suchoscillations, said. means comprising metallic conductors adapted to becon led with a circuit carrying the electrical oscillations to besupplied to said acoustic device.

11. Acoustic apparatus comprising an acoustic device adapted to convertelectrical oscillations into sound waves corresponding thereto, ayielding and flexible covering having minimum acoustic dampingcharacteristics mounted upon said acoustic device and means associatedtherewith, for sup l ying electrical oscillations to said acousticwithout metallic connection to the source 0% such oscillations, saidmeans comprising metallic conductors adapted to be cou led with acircuit carrying the electrical oscillations to be supplied to saidacoustic device, and means for amplifying the oscillations produced insaid conductors all of said apparatus being mounted within saidcovering.

12. Acoustic apparatus comprising an acoustic. device adapted to convertelectrical oscillations into sound waves corresponding thereto, ayielding and flexible covering having minimum acoustic dampingcharacteristlcsmounted on said acoustic device, and means associatedtherewith for supplying electrical oscillations 'to said acoustic devicewithout metallic connection to the source of such oscillations, saidmeans comprising metallic conductors ada ted to be coupled with acircuit carrying t e oscillations to be supplied to said acousticdevice, a frequency selecting circuit, and means for amplifying thereceived oscillations, and flexible means for varying the operatingcharacteristics of desired parts of such apparatus and extending throughsaid coverm all of said apparatus being mounted within said covering.

13. Acoustic apparatus comprising an acoustic device adapted to convertelectrical oscillations into sound waves corresponding thereto, aresilient and flexible covering having minimum acoustic dampingcharacterisstics mounted on said acoustic device and means associatedtherewith for supplying electrical oscillations to said acoustic devicewithout metallic connection to the source of such oscillations, saidmeans comprising metallic conductors adapted to be coupled with acircuit carrying the oscillations to be supplied to said acousticdevice, a frequency selecting circuit, a detector and means foramplifying the received oscillations and flexible means for varying theoperating characteristics of desire parts of such apparatus andextending through said covering all of evice said apparatus beingmounted within said covering.

14. Acoustic apparatus comprising in combination, a framework, audiofrequency amplifying apparatus mounted thereon, a sound reproducercarried thereby and connected to said amplifying apparatus, and aresilient covering mounted on said framework over said amplifyingapparatus and loud speaker to support the ear of the listener inintimate and comfortable proximity to said loud speaker.

15. Acoustic apparatus comprising in combination, a framework, radioreceiving apparatus mounted on said framework, a sound reproducercarried thereby and operable by said receiving apparatus and a resilientcovering mounted thereon over said receiving apparatus to support theear of the listener in intimate and comfortable proximity to said loudspeaker.

16. Acoustic apparatus comprising in combination, an electricallyoperable sound reproducer, a resilient and flexible covering extendingover the sound radiating portion of said reproducer, and constructed andarranged to support the ear of a listener in intimate and comfortableproximity thereto, said covering comprising a resilient body permittingthe passage of sound therethrough.

l7. Acoustic apparatus comprising in combination, an electricallyoperable sound reproducer, a resilient and flexible covering extendingover the sound radiating portion of said reproducer and constructed andarranged to conform to and comfortably support the ear of a listener inproximity to said sound reproducer, said covering comprising a layer ofresilient material permeated with air spaces.

Signed at New York city in the county of New York and State of New Yorkthis 8th day of June A. D. 1927.

ALEXANDER McLEAN NICOLSON.

